United Boeing 777 nosedive

[TCAS II]

United flight 1722: US to investigate Boeing 777's mysterious nosedive https://www.bbc.co.uk/news/world-us-canada-64645457

US air safety officials say they will investigate why a Boeing 777 jet unexpectedly lost altitude and nearly plunged into the Pacific Ocean.

United Airlines flight 1722 had left Maui on 18 December and was climbing when it suddenly plummeted 1,400ft (425m), reports say.

It stabilised at just 775ft in altitude and went on to land safely in San Francisco 27 minutes early.

Its adds to a number of near misses involving planes this year.

The flight was going normally until 71 seconds after take-off from Kahului Airport when it suddenly dropped in elevation, according to Flightradar24, an aviation website.

The National Transportation Safety Board (NTSB), which investigates US plane crashes, will produce a report about the incident within three weeks.

Passenger Rod Williams told CNN: "There were a number of screams on the plane. Everybody knew that something was out of the ordinary, or at least that this was not normal."

He said it was "sobering" to think they were probably about five seconds away from hitting the water

The flight's pilots filed an internal safety report after landing, a United Airlines representative told BBC News. They have a combined 25,000 hours of flying experience.

An investigation by the airline resulted in additional training for the pilots, which United said was ongoing.

"Safety remains our highest priority," a company official said in a statement.

The Federal Aviation Administration (FAA) also received a report of the incident, the federal agency says, and "took appropriate action". It did not elaborate.

The incident is among a number of potentially dangerous events reported by US airlines recently, including two near misses in New York and Texas this year.

The NTSB is already looking into two close calls within the last month.

On 4 February, a FedEx cargo plane aborted its landing to avoid a Southwest Airlines plane at Austin-Bergstrom International Airport in Texas.

At John F Kennedy Airport in New York in January, a Delta flight stopped short on the runway during take-off to avoid an American Airlines plane.

[digits_]

Hmmm

- nose dive after take-off
- they continued crossing the pacific instead of returning
- company gives pilots more training

Seems like finger trouble then?

I *hope* they wouldn't have taken a 777 across the Pacific if there were undiagnosed flight control issues....

[Donald]

I've seen some online speculation about a microburst downdraft. What was the weather in the area?

[Eric Janson]

I've seen some online speculation about a microburst downdraft. What was the weather in the area?

Altitude profile shows nothing to suggest a microburst.

The statement that both Pilots are being 're-trained' would seem to indicate aircraft mis-handling of some kind.

The FAA has opened an investigation - so we will know more in a month or so.

[rudder]

If the altitude box is set to ‘0000’ and you select FLCH leaving 1000’ AGL - where will the FD/AP take you on a 777?

[DanWEC]

Also, I'll be curious to hear if the recovery was done on automation or if they disconnected ....

[pelmet]

If the altitude box is set to ‘0000’ and you select FLCH leaving 1000’ AGL - where will the FD/AP take you on a 777?

Pretty unusual to use FLCH in such a situation. But unusual things do happen. I have seen two high time captains get themselves into steep turns at low level on departure at night. Both times it was manual flying and deciding to start playing with the FMC/navigation box while in a turn, instead of asking for assistance.

[digits_]

PPRUNE rumours claim captain was PF. FO raised flaps from F20 to F1 instead of F5. Captain looked down to see what was going on, got a bit disoriented and turned (stalled? wing drop?) the plane in the process. They recovered, made an ''all is well folks" PA and proceeded on course.

[Eric Janson]

PPRUNE rumours claim captain was PF. FO raised flaps from F20 to F1 instead of F5. Captain looked down to see what was going on, got a bit disoriented and turned (stalled? wing drop?) the plane in the process. They recovered, made an ''all is well folks" PA and proceeded on course.

Disclaimer:- Don’t fly the 777.

I’m assuming most T/O done with flap 1 or 5. With a flap 5 T/O the first retraction is from 5 to 1.

If you don’t do many flap 20 take-off then I can see the 20 to 5 step becoming 20 to 1 to match what what is normally done. The call is ‘Flap 5’ - be interesting to see what was called.

Luckily there is a gate at flap 1.

If I remember correctly a single engine go-around has the flaps go from 20 to 1 - somebody that flies Boeing 777 please confirm?

Tip:- There is no rush to retract flaps - think about what you are going to do before moving the lever. In Nepal it looks like the engines were feathered instead of flaps being selected.

[RB211]

Disclaimer:- Don’t fly the 777.

I’m assuming most T/O done with flap 1 or 5. With a flap 5 T/O the first retraction is from 5 to 1.

If you don’t do many flap 20 take-off then I can see the 20 to 5 step becoming 20 to 1 to match what what is normally done. The call is ‘Flap 5’ - be interesting to see what was called.

Luckily there is a gate at flap 1.

If I remember correctly a single engine go-around has the flaps go from 20 to 1 - somebody that flies Boeing 777 please confirm?

Tip:- There is no rush to retract flaps - think about what you are going to do before moving the lever. In Nepal it looks like the engines were feathered instead of flaps being selected.

Flap settings are Up, 1, 5, 15, 20, 25 and 30.

Take off Flap settings are 5, 15 or 20.

Slats are extended to midrange at Fl 1 selection and to landing position with Fl 25.

The gate at Fl 20 prevents inadvertent retraction of Flaps passed the go-around Flap setting. The gate at Flap 1 prevents inadvertent retraction of the Slats passed the mid range position.

Single engine go-around, if planned landing was Fl 20, Flap selection is 20 to 5.

Moving the Flap lever to a given Flap setting displays on the EICAS in magenta and turns green when commanded position is reached.

Speed tape displays Flap maneuvering speed for Flap extension/retraction.

As you mentioned, no need to rush. Move the lever to the next requested position, pause a moment and ensure what you want is displayed in magenta.

[pelmet]

Disclaimer:- Don’t fly the 777.

I’m assuming most T/O done with flap 1 or 5. With a flap 5 T/O the first retraction is from 5 to 1.

If you don’t do many flap 20 take-off then I can see the 20 to 5 step becoming 20 to 1 to match what what is normally done. The call is ‘Flap 5’ - be interesting to see what was called.

Luckily there is a gate at flap 1.

If I remember correctly a single engine go-around has the flaps go from 20 to 1 - somebody that flies Boeing 777 please confirm?

Tip:- There is no rush to retract flaps - think about what you are going to do before moving the lever. In Nepal it looks like the engines were feathered instead of flaps being selected.

Flap settings are Up, 1, 5, 15, 20, 25 and 30.

Take off Flap settings are 5, 15 or 20.

Slats are extended to midrange at Fl 1 selection and to landing position with Fl 25.

The gate at Fl 20 prevents inadvertent retraction of Flaps passed the go-around Flap setting. The gate at Flap 1 prevents inadvertent retraction of the Slats passed the mid range position.

Single engine go-around, if planned landing was Fl 20, Flap selection is 20 to 5.

Moving the Flap lever to a given Flap setting displays on the EICAS in magenta and turns green when commanded position is reached.

Speed tape displays Flap maneuvering speed for Flap extension/retraction.

As you mentioned, no need to rush. Move the lever to the next requested position, pause a moment and ensure what you want is displayed in magenta.

It is not just making sure not to rush. One needs to look carefully at their selection. The modern Boeings are fairly similar. After takeoff, the PF calls for flaps 5. Make sure that it was the correct call, repeat the call to ingrain it in your short term memory, look at what you are reaching for, and look at where it is being positioned as is possible to grab the wrong item (like that ATR crash recently where condition levers were moved instead of flaps).

Then look where you are moving the flap handle to by seeing the flap 5 detent. It can be easily missed and bypassed. Once the flap lever is in the detent, look for the number 5 to be displayed on the flap indicator. In all, this takes perhaps two of three seconds.All done methodically and at a measured pace. Fast hands are dangerous hands in a cockpit.

I embarrassed myself many years ago on a line check by grabbing the gust lock lever and attempting to move it when the captain called for a flap selection. Became methodical after that and have never had an issue since. But my methodical procedure(which probably most people use) has allowed me to catch myself heading toward a wrong flap selection more than once.

[Eric Janson]

Report released by the NTSB.

https://avherald.com/h?article=50526a09&opt=0

From the report:-

14:50:51– Vertical speed and pitch attitude continued a negative downward trend to reach a maximum of -8,536 feet per minute and -16.74 degrees respectively while at 1,386 feet (radio altitude).

3. The lowest radio altitude during the undesired aircraft state was 748 feet

Unbelievable.